Sorting Plastics

Objective: To develop a procedure for separating assorted, unidentified plastic pellets using the concept of density.

Background: When a Materials Recycling Facility gets a load of mixed plastic, they need to separate it into different types before they can re-sell it. Number 1 plastic is great for carpeting, but not for plastic decking "lumber"; number 2 plastic is great for plastic decking "lumber", but not for carpeting.

Since the six types of plastic have different densities, you could devise a plan to put plastic bits into a vat of liquid and adjust the density of that liquid until different types of plastic rise to the top. You will be given isopropyl alcohol, water, and the ability to mix them. You will be given an assortment of unidentified plastic pellets. You need to develop a plan to sort them by type!